On Wed, 29 Nov 2006, akpm@xxxxxxxx wrote: > > The patch titled > ext3 balloc: fix _with_rsv freeze > has been added to the -mm tree. Its filename is > ext3-balloc-fix-_with_rsv-freeze.patch > > See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find > out what to do about this > > ------------------------------------------------------ > Subject: ext3 balloc: fix _with_rsv freeze > From: Hugh Dickins <hugh@xxxxxxxxxxx> > > After several days of testing ext3 with reservations, it got caught inside > ext3_try_to_allocate_with_rsv: alloc_new_reservation repeatedly succeeding > on the window [12cff,12d0e], ext3_try_to_allocate repeatedly failing to > find the free block guaranteed to be included (unless there's contention). Thanks a lot for changing the comments on these twelve, substituting ext3 or ext4 for ext2 where appropriate: I much prefer these. But in the case of this ext3-balloc-fix-_with_rsv-freeze.patch and the ext4-balloc-fix-_with_rsv-freeze.patch, the resulting comment goes wrong: there's never been such a freeze in ext3 or ext4. I suggest a better comment for this ext3 one would be something like the below - I trust you to deduce the ext4 comment! Port fix to the off-by-one in find_next_usable_block's memscan from ext2 to ext3; but it didn't cause a serious problem for ext3 because the additional ext3_test_allocatable check rescued it from the error. Hugh > > Fix the range to find_next_usable_block's memscan: the scan from "here" > (0xcfe) up to (but excluding) "maxblocks" (0xd0e) needs to scan 3 bytes not > 2 (the relevant bytes of bitmap in this case being f7 df ff - none 00, but > the premature cutoff implying that the last was found 00). > > Is this a problem for mainline ext3? No, because the "size" in its memscan > is always EXT2_BLOCKS_PER_GROUP(sb), which mkfs.ext3 requires to be a > multiple of 8. Is this a problem for ext3 or ext4? No, because they have > an additional extN_test_allocatable test which rescues them from the error. > > Signed-off-by: Mingming Cao <cmm@xxxxxxxxxx> > Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx> > Cc: <linux-ext4@xxxxxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxx> > --- > > fs/ext3/balloc.c | 2 +- > 1 files changed, 1 insertion(+), 1 deletion(-) > > diff -puN fs/ext3/balloc.c~ext3-balloc-fix-_with_rsv-freeze fs/ext3/balloc.c > --- a/fs/ext3/balloc.c~ext3-balloc-fix-_with_rsv-freeze > +++ a/fs/ext3/balloc.c > @@ -730,7 +730,7 @@ find_next_usable_block(ext3_grpblk_t sta > here = 0; > > p = ((char *)bh->b_data) + (here >> 3); > - r = memscan(p, 0, (maxblocks - here + 7) >> 3); > + r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3)); > next = (r - ((char *)bh->b_data)) << 3; > > if (next < maxblocks && next >= start && ext3_test_allocatable(next, bh)) > _ > > Patches currently in -mm which might be from hugh@xxxxxxxxxxx are > > git-powerpc.patch > __unmap_hugepage_range-add-comment.patch > shared-page-table-for-hugetlb-page-v4.patch > htlb-forget-rss-with-pt-sharing.patch > mlock-cleanup.patch > always-print-out-the-header-line-in-proc-swaps.patch > reject-corrupt-swapfiles-earlier.patch > kill-install_file_ptes-pte_val.patch > honour-mnt_noexec-for-access.patch > ext3-fix-reservation-extension.patch > ext4-fix-reservation-extension.patch > ext3-balloc-reset-windowsz-when-full.patch > ext3-balloc-fix-off-by-one-against-grp_goal.patch > ext3-balloc-fix-off-by-one-against-rsv_end.patch > ext3-balloc-say-rb_entry-not-list_entry.patch > ext3-balloc-use-io_error-label.patch > ext3-balloc-fix-_with_rsv-freeze.patch > ext2-reservations.patch > ext2-balloc-fix-_with_rsv-freeze.patch > ext2-balloc-reset-windowsz-when-full.patch > ext2-balloc-fix-off-by-one-against-rsv_end.patch > ext2-balloc-fix-off-by-one-against-grp_goal.patch > ext2-balloc-say-rb_entry-not-list_entry.patch > ext2-balloc-use-io_error-label.patch > generic-bug-implementation.patch > generic-bug-implementation-handle-bug=n.patch > generic-bug-for-i386.patch > generic-bug-for-x86-64.patch > bug-test-1.patch > tty-switch-to-ktermios-powerpc-fix.patch - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
